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<FONT color="green">001</FONT>    package org.codemonkey.swiftsocketclient;<a name="line.1"></a>
<FONT color="green">002</FONT>    <a name="line.2"></a>
<FONT color="green">003</FONT>    import java.io.IOException;<a name="line.3"></a>
<FONT color="green">004</FONT>    import java.net.DatagramPacket;<a name="line.4"></a>
<FONT color="green">005</FONT>    import java.net.DatagramSocket;<a name="line.5"></a>
<FONT color="green">006</FONT>    import java.net.InetSocketAddress;<a name="line.6"></a>
<FONT color="green">007</FONT>    import java.net.ServerSocket;<a name="line.7"></a>
<FONT color="green">008</FONT>    import java.net.Socket;<a name="line.8"></a>
<FONT color="green">009</FONT>    import java.net.SocketException;<a name="line.9"></a>
<FONT color="green">010</FONT>    import java.util.LinkedList;<a name="line.10"></a>
<FONT color="green">011</FONT>    <a name="line.11"></a>
<FONT color="green">012</FONT>    import org.apache.log4j.Logger;<a name="line.12"></a>
<FONT color="green">013</FONT>    <a name="line.13"></a>
<FONT color="green">014</FONT>    /**<a name="line.14"></a>
<FONT color="green">015</FONT>     * Abstraction of the client socket. Acts as a wrapper for {@link Socket} and {@link DatagramSocket} to provide uniform behavior.<a name="line.15"></a>
<FONT color="green">016</FONT>     * <a name="line.16"></a>
<FONT color="green">017</FONT>     * @author Benny Bottema<a name="line.17"></a>
<FONT color="green">018</FONT>     * @see ClientEndpointTCP<a name="line.18"></a>
<FONT color="green">019</FONT>     * @see ClientEndpointUDP<a name="line.19"></a>
<FONT color="green">020</FONT>     * @since 1.0<a name="line.20"></a>
<FONT color="green">021</FONT>     */<a name="line.21"></a>
<FONT color="green">022</FONT>    interface ClientEndpoint {<a name="line.22"></a>
<FONT color="green">023</FONT>            /**<a name="line.23"></a>
<FONT color="green">024</FONT>             * All subclasses use the logger anchored to &lt;code&gt;ClientEndpoint.class&lt;/code&gt;.<a name="line.24"></a>
<FONT color="green">025</FONT>             */<a name="line.25"></a>
<FONT color="green">026</FONT>            public static final Logger LOGGER = Logger.getLogger(ClientEndpoint.class);<a name="line.26"></a>
<FONT color="green">027</FONT>    <a name="line.27"></a>
<FONT color="green">028</FONT>            /**<a name="line.28"></a>
<FONT color="green">029</FONT>             * @return An endpoint that acts similarly for a TCP and UDP server.<a name="line.29"></a>
<FONT color="green">030</FONT>             * @throws IOException Thrown by {@link ClientEndpointTCP#getServerEndpoint()}<a name="line.30"></a>
<FONT color="green">031</FONT>             */<a name="line.31"></a>
<FONT color="green">032</FONT>            ServerEndpoint getServerEndpoint()<a name="line.32"></a>
<FONT color="green">033</FONT>                            throws IOException;<a name="line.33"></a>
<FONT color="green">034</FONT>    <a name="line.34"></a>
<FONT color="green">035</FONT>            /**<a name="line.35"></a>
<FONT color="green">036</FONT>             * @return Whether an explicitly call has been made to {@link ClientEndpoint#close()} or close on the passed in socket (both TCP and<a name="line.36"></a>
<FONT color="green">037</FONT>             *         UDP).<a name="line.37"></a>
<FONT color="green">038</FONT>             */<a name="line.38"></a>
<FONT color="green">039</FONT>            boolean isClosed();<a name="line.39"></a>
<FONT color="green">040</FONT>    <a name="line.40"></a>
<FONT color="green">041</FONT>            /**<a name="line.41"></a>
<FONT color="green">042</FONT>             * Call the close method on the embedded socket (works for both TCP and UDP).<a name="line.42"></a>
<FONT color="green">043</FONT>             * <a name="line.43"></a>
<FONT color="green">044</FONT>             * @throws IOException Thrown by {@link ClientEndpointTCP#close()}<a name="line.44"></a>
<FONT color="green">045</FONT>             */<a name="line.45"></a>
<FONT color="green">046</FONT>            void close()<a name="line.46"></a>
<FONT color="green">047</FONT>                            throws IOException;<a name="line.47"></a>
<FONT color="green">048</FONT>    }<a name="line.48"></a>
<FONT color="green">049</FONT>    <a name="line.49"></a>
<FONT color="green">050</FONT>    /**<a name="line.50"></a>
<FONT color="green">051</FONT>     * Wrapper that delegates all calls directly to the decorated {@link Socket}. The Client Endpoint abstraction mimics how TCP deals with a<a name="line.51"></a>
<FONT color="green">052</FONT>     * server and so the TCP client endpoint variant adds no extra functionality, except that it returns the server endpoint instead of the<a name="line.52"></a>
<FONT color="green">053</FONT>     * {@link Socket} instance itself (see {@link #getServerEndpoint()}.<a name="line.53"></a>
<FONT color="green">054</FONT>     * <a name="line.54"></a>
<FONT color="green">055</FONT>     * @author Benny Bottema<a name="line.55"></a>
<FONT color="green">056</FONT>     * @since 1.0<a name="line.56"></a>
<FONT color="green">057</FONT>     */<a name="line.57"></a>
<FONT color="green">058</FONT>    class ClientEndpointTCP implements ClientEndpoint {<a name="line.58"></a>
<FONT color="green">059</FONT>    <a name="line.59"></a>
<FONT color="green">060</FONT>            private final Socket clientSocket;<a name="line.60"></a>
<FONT color="green">061</FONT>    <a name="line.61"></a>
<FONT color="green">062</FONT>            /**<a name="line.62"></a>
<FONT color="green">063</FONT>             * Constructor; simply stores a reference to the client socket.<a name="line.63"></a>
<FONT color="green">064</FONT>             * <a name="line.64"></a>
<FONT color="green">065</FONT>             * @param clientSocket The {@link Socket} on which we connect new clients.<a name="line.65"></a>
<FONT color="green">066</FONT>             */<a name="line.66"></a>
<FONT color="green">067</FONT>            public ClientEndpointTCP(final Socket clientSocket) {<a name="line.67"></a>
<FONT color="green">068</FONT>                    this.clientSocket = clientSocket;<a name="line.68"></a>
<FONT color="green">069</FONT>            }<a name="line.69"></a>
<FONT color="green">070</FONT>    <a name="line.70"></a>
<FONT color="green">071</FONT>            /**<a name="line.71"></a>
<FONT color="green">072</FONT>             * Returns a new {@link ServerEndpointTCP} {@link Socket} decorator (which passed in the constructor).<a name="line.72"></a>
<FONT color="green">073</FONT>             * <a name="line.73"></a>
<FONT color="green">074</FONT>             * @throws IOException Thrown by {@link ServerEndpointTCP#ServerEndpointTCP(Socket)}.<a name="line.74"></a>
<FONT color="green">075</FONT>             */<a name="line.75"></a>
<FONT color="green">076</FONT>            @Override<a name="line.76"></a>
<FONT color="green">077</FONT>            public ServerEndpoint getServerEndpoint()<a name="line.77"></a>
<FONT color="green">078</FONT>                            throws IOException {<a name="line.78"></a>
<FONT color="green">079</FONT>                    return new ServerEndpointTCP(clientSocket);<a name="line.79"></a>
<FONT color="green">080</FONT>            }<a name="line.80"></a>
<FONT color="green">081</FONT>    <a name="line.81"></a>
<FONT color="green">082</FONT>            /**<a name="line.82"></a>
<FONT color="green">083</FONT>             * @return {@link Socket#isClosed()}<a name="line.83"></a>
<FONT color="green">084</FONT>             */<a name="line.84"></a>
<FONT color="green">085</FONT>            @Override<a name="line.85"></a>
<FONT color="green">086</FONT>            public boolean isClosed() {<a name="line.86"></a>
<FONT color="green">087</FONT>                    return clientSocket.isClosed();<a name="line.87"></a>
<FONT color="green">088</FONT>            }<a name="line.88"></a>
<FONT color="green">089</FONT>    <a name="line.89"></a>
<FONT color="green">090</FONT>            /**<a name="line.90"></a>
<FONT color="green">091</FONT>             * Calls {@link Socket#close()}.<a name="line.91"></a>
<FONT color="green">092</FONT>             * <a name="line.92"></a>
<FONT color="green">093</FONT>             * @throws IOException Thrown by {@link Socket#close()}.<a name="line.93"></a>
<FONT color="green">094</FONT>             */<a name="line.94"></a>
<FONT color="green">095</FONT>            @Override<a name="line.95"></a>
<FONT color="green">096</FONT>            public void close()<a name="line.96"></a>
<FONT color="green">097</FONT>                            throws IOException {<a name="line.97"></a>
<FONT color="green">098</FONT>                    clientSocket.close();<a name="line.98"></a>
<FONT color="green">099</FONT>            }<a name="line.99"></a>
<FONT color="green">100</FONT>    }<a name="line.100"></a>
<FONT color="green">101</FONT>    <a name="line.101"></a>
<FONT color="green">102</FONT>    /**<a name="line.102"></a>
<FONT color="green">103</FONT>     * Wrapper that adds TCP like server handling to the UDP {@link DatagramSocket}.<a name="line.103"></a>
<FONT color="green">104</FONT>     * <a name="line.104"></a>
<FONT color="green">105</FONT>     * @author Benny Bottema<a name="line.105"></a>
<FONT color="green">106</FONT>     * @see #ClientEndpointUDP<a name="line.106"></a>
<FONT color="green">107</FONT>     * @see #getServerEndpoint()<a name="line.107"></a>
<FONT color="green">108</FONT>     * @see DatagramPacketReceiver<a name="line.108"></a>
<FONT color="green">109</FONT>     * @since 1.0<a name="line.109"></a>
<FONT color="green">110</FONT>     */<a name="line.110"></a>
<FONT color="green">111</FONT>    class ClientEndpointUDP implements ClientEndpoint {<a name="line.111"></a>
<FONT color="green">112</FONT>    <a name="line.112"></a>
<FONT color="green">113</FONT>            /**<a name="line.113"></a>
<FONT color="green">114</FONT>             * This should probably be tuned at some point to allow for larger datagram packets.<a name="line.114"></a>
<FONT color="green">115</FONT>             */<a name="line.115"></a>
<FONT color="green">116</FONT>            private static final int PACKET_BUFFER_SIZE = 1024;<a name="line.116"></a>
<FONT color="green">117</FONT>    <a name="line.117"></a>
<FONT color="green">118</FONT>            /**<a name="line.118"></a>
<FONT color="green">119</FONT>             * Contains the that is the first value we expect from the server as an acknowledgment answer to '{@value #CONNECT}'.<a name="line.119"></a>
<FONT color="green">120</FONT>             * &lt;p&gt;<a name="line.120"></a>
<FONT color="green">121</FONT>             * Value: {@value #ACK}.<a name="line.121"></a>
<FONT color="green">122</FONT>             */<a name="line.122"></a>
<FONT color="green">123</FONT>            public static final String ACK = "ACK";<a name="line.123"></a>
<FONT color="green">124</FONT>            /**<a name="line.124"></a>
<FONT color="green">125</FONT>             * Contains the value that is the command sent to the server when making first contact, so that the server knows where to send the UDP<a name="line.125"></a>
<FONT color="green">126</FONT>             * messages.<a name="line.126"></a>
<FONT color="green">127</FONT>             * &lt;p&gt;<a name="line.127"></a>
<FONT color="green">128</FONT>             * Value: {@value #CONNECT}.<a name="line.128"></a>
<FONT color="green">129</FONT>             */<a name="line.129"></a>
<FONT color="green">130</FONT>            public static final String CONNECT = "CONNECT";<a name="line.130"></a>
<FONT color="green">131</FONT>    <a name="line.131"></a>
<FONT color="green">132</FONT>            /**<a name="line.132"></a>
<FONT color="green">133</FONT>             * The client socket on which we'll send and receive messages on in the form of UDP datagram packets.<a name="line.133"></a>
<FONT color="green">134</FONT>             */<a name="line.134"></a>
<FONT color="green">135</FONT>            private final DatagramSocket datagramSocket;<a name="line.135"></a>
<FONT color="green">136</FONT>    <a name="line.136"></a>
<FONT color="green">137</FONT>            /**<a name="line.137"></a>
<FONT color="green">138</FONT>             * The server endpoint, assigned when first UDP contact has been made. We can't know the address before that, as the server is<a name="line.138"></a>
<FONT color="green">139</FONT>             * identified by the UDP packet.<a name="line.139"></a>
<FONT color="green">140</FONT>             */<a name="line.140"></a>
<FONT color="green">141</FONT>            private ServerEndpointUDP server;<a name="line.141"></a>
<FONT color="green">142</FONT>    <a name="line.142"></a>
<FONT color="green">143</FONT>            /**<a name="line.143"></a>
<FONT color="green">144</FONT>             * When initializing a connection to the server, we're performing a handshake which needs to be acknowledged first. Since UDP does not<a name="line.144"></a>
<FONT color="green">145</FONT>             * guarantee the order of incoming message, we might need to buffer unrelated message until the acknowledgment arrives.<a name="line.145"></a>
<FONT color="green">146</FONT>             */<a name="line.146"></a>
<FONT color="green">147</FONT>            private boolean handshakeAcknowledged;<a name="line.147"></a>
<FONT color="green">148</FONT>    <a name="line.148"></a>
<FONT color="green">149</FONT>            /**<a name="line.149"></a>
<FONT color="green">150</FONT>             * This queue buffers incoming messages while the handshake is being confirmed by the server.<a name="line.150"></a>
<FONT color="green">151</FONT>             */<a name="line.151"></a>
<FONT color="green">152</FONT>            private final LinkedList&lt;DatagramPacket&gt; bufferQueue;<a name="line.152"></a>
<FONT color="green">153</FONT>    <a name="line.153"></a>
<FONT color="green">154</FONT>            /**<a name="line.154"></a>
<FONT color="green">155</FONT>             * Constructor; starts a new &lt;code&gt;Thread&lt;/code&gt; listening for new datagram packets. If a new server sends a message, it will be<a name="line.155"></a>
<FONT color="green">156</FONT>             * returned on {@link #getServerEndpoint()}. In either case the datagram is passed on to the server endpoint.<a name="line.156"></a>
<FONT color="green">157</FONT>             * <a name="line.157"></a>
<FONT color="green">158</FONT>             * @param datagramSocket A DatagramSocket to listen to UDP messages.<a name="line.158"></a>
<FONT color="green">159</FONT>             * @param host The host to which the {@link DatagramPacket} objects need to be sent to.<a name="line.159"></a>
<FONT color="green">160</FONT>             * @param port The host to which the {@link DatagramPacket} objects need to be sent to.<a name="line.160"></a>
<FONT color="green">161</FONT>             */<a name="line.161"></a>
<FONT color="green">162</FONT>            public ClientEndpointUDP(final DatagramSocket datagramSocket, final String host, final int port) {<a name="line.162"></a>
<FONT color="green">163</FONT>                    this.datagramSocket = datagramSocket;<a name="line.163"></a>
<FONT color="green">164</FONT>                    handshakeAcknowledged = false;<a name="line.164"></a>
<FONT color="green">165</FONT>                    bufferQueue = new LinkedList&lt;DatagramPacket&gt;();<a name="line.165"></a>
<FONT color="green">166</FONT>                    initializeHandshake(host, port);<a name="line.166"></a>
<FONT color="green">167</FONT>                    new Thread(new DatagramPacketReceiver()).start();<a name="line.167"></a>
<FONT color="green">168</FONT>                    // block the client until connection has been completely established<a name="line.168"></a>
<FONT color="green">169</FONT>                    while (!handshakeAcknowledged) {<a name="line.169"></a>
<FONT color="green">170</FONT>                            ServerUtil.defaultSleep();<a name="line.170"></a>
<FONT color="green">171</FONT>                    }<a name="line.171"></a>
<FONT color="green">172</FONT>            }<a name="line.172"></a>
<FONT color="green">173</FONT>    <a name="line.173"></a>
<FONT color="green">174</FONT>            /**<a name="line.174"></a>
<FONT color="green">175</FONT>             * Performs a handshake with the server by sending a '{@value #CONNECT}' command. The response '{@value #ACK}' is handled by<a name="line.175"></a>
<FONT color="green">176</FONT>             * {@link DatagramPacketReceiver#run()}.<a name="line.176"></a>
<FONT color="green">177</FONT>             * <a name="line.177"></a>
<FONT color="green">178</FONT>             * @param host The host to which the {@link DatagramPacket} objects need to be sent to.<a name="line.178"></a>
<FONT color="green">179</FONT>             * @param port The host to which the {@link DatagramPacket} objects need to be sent to.<a name="line.179"></a>
<FONT color="green">180</FONT>             */<a name="line.180"></a>
<FONT color="green">181</FONT>            private void initializeHandshake(final String host, final int port) {<a name="line.181"></a>
<FONT color="green">182</FONT>                    LOGGER.info("offering server a handshake");<a name="line.182"></a>
<FONT color="green">183</FONT>                    final InetSocketAddress serverAddress = new InetSocketAddress(host, port);<a name="line.183"></a>
<FONT color="green">184</FONT>                    try {<a name="line.184"></a>
<FONT color="green">185</FONT>                            datagramSocket.send(new DatagramPacket(CONNECT.getBytes(), CONNECT.length(), serverAddress));<a name="line.185"></a>
<FONT color="green">186</FONT>                    } catch (final SocketException e) {<a name="line.186"></a>
<FONT color="green">187</FONT>                            throw new RuntimeException("unable to create UDP datagram packet", e);<a name="line.187"></a>
<FONT color="green">188</FONT>                    } catch (final IOException e) {<a name="line.188"></a>
<FONT color="green">189</FONT>                            throw new RuntimeException(e);<a name="line.189"></a>
<FONT color="green">190</FONT>                    }<a name="line.190"></a>
<FONT color="green">191</FONT>            }<a name="line.191"></a>
<FONT color="green">192</FONT>    <a name="line.192"></a>
<FONT color="green">193</FONT>            /**<a name="line.193"></a>
<FONT color="green">194</FONT>             * Continuously receives {@link DatagramPacket} objects and delegates these to a {@link ServerEndpoint} to emulate TCP {@link Socket}<a name="line.194"></a>
<FONT color="green">195</FONT>             * behavior where a &lt;code&gt;Socket&lt;/code&gt; per server receives messages from a connected client. Except there will always be one socket<a name="line.195"></a>
<FONT color="green">196</FONT>             * associated with this client endpoint, since there can only be one server instance.<a name="line.196"></a>
<FONT color="green">197</FONT>             * &lt;p&gt;<a name="line.197"></a>
<FONT color="green">198</FONT>             * If the server has not been assigned using a {@link ServerEndpointUDP}, we will do so with the first datagram packet we receive, which<a name="line.198"></a>
<FONT color="green">199</FONT>             * must also be an {@value ServerEndpointUDP#ACK}. If confirmed, the {@link DatagramSocket} is embedded in a {@link ServerEndpointUDP}.<a name="line.199"></a>
<FONT color="green">200</FONT>             * By abstracting this behavior in 'server endpoints', we can now for both TCP Socket messages and datagram packets act as though the<a name="line.200"></a>
<FONT color="green">201</FONT>             * endpoint received it directly from a client and so have consistent and uniform behavior for handling TCP and UDP messages. The only<a name="line.201"></a>
<FONT color="green">202</FONT>             * downside to this is that we cannot detect a client dropping the connection (so PingPong mode is advised).<a name="line.202"></a>
<FONT color="green">203</FONT>             * <a name="line.203"></a>
<FONT color="green">204</FONT>             * @author Benny Bottema<a name="line.204"></a>
<FONT color="green">205</FONT>             * @see #verifyAcknowledgment(DatagramPacket)<a name="line.205"></a>
<FONT color="green">206</FONT>             * @since 1.0<a name="line.206"></a>
<FONT color="green">207</FONT>             */<a name="line.207"></a>
<FONT color="green">208</FONT>            private class DatagramPacketReceiver implements Runnable {<a name="line.208"></a>
<FONT color="green">209</FONT>                    @Override<a name="line.209"></a>
<FONT color="green">210</FONT>                    public void run() {<a name="line.210"></a>
<FONT color="green">211</FONT>                            // a DatagramSocket will only close if the client is stopping gracefully<a name="line.211"></a>
<FONT color="green">212</FONT>                            while (!datagramSocket.isClosed()) {<a name="line.212"></a>
<FONT color="green">213</FONT>                                    final DatagramPacket datagramPacket = new DatagramPacket(new byte[PACKET_BUFFER_SIZE], PACKET_BUFFER_SIZE);<a name="line.213"></a>
<FONT color="green">214</FONT>                                    try {<a name="line.214"></a>
<FONT color="green">215</FONT>                                            datagramSocket.receive(datagramPacket);<a name="line.215"></a>
<FONT color="green">216</FONT>                                    } catch (final IOException e) {<a name="line.216"></a>
<FONT color="green">217</FONT>                                            LOGGER.error("error waiting for new datagram packet in UDP client endpoint", e);<a name="line.217"></a>
<FONT color="green">218</FONT>                                            continue; // should we continue? if we don't we'll have a complete server crash on our hands<a name="line.218"></a>
<FONT color="green">219</FONT>                                    }<a name="line.219"></a>
<FONT color="green">220</FONT>                                    if (LOGGER.isTraceEnabled()) {<a name="line.220"></a>
<FONT color="green">221</FONT>                                            String messageReceived = new String(datagramPacket.getData());<a name="line.221"></a>
<FONT color="green">222</FONT>                                            String msg = "datagram packet received from %s, message: %s";<a name="line.222"></a>
<FONT color="green">223</FONT>                                            LOGGER.trace(String.format(msg, datagramPacket.getSocketAddress(), messageReceived));<a name="line.223"></a>
<FONT color="green">224</FONT>                                    }<a name="line.224"></a>
<FONT color="green">225</FONT>                                    if (server == null) {<a name="line.225"></a>
<FONT color="green">226</FONT>                                            final String msg = "received UDP datagram packet from new server endpoint [%s]";<a name="line.226"></a>
<FONT color="green">227</FONT>                                            LOGGER.debug(String.format(msg, datagramPacket.getSocketAddress()));<a name="line.227"></a>
<FONT color="green">228</FONT>                                            server = new ServerEndpointUDP(datagramSocket, datagramPacket.getAddress(), datagramPacket.getSocketAddress());<a name="line.228"></a>
<FONT color="green">229</FONT>                                    } else {<a name="line.229"></a>
<FONT color="green">230</FONT>                                            final String msg = "received UDP datagram packet from known server endpoint [%s]";<a name="line.230"></a>
<FONT color="green">231</FONT>                                            LOGGER.debug(String.format(msg, datagramPacket.getSocketAddress()));<a name="line.231"></a>
<FONT color="green">232</FONT>                                    }<a name="line.232"></a>
<FONT color="green">233</FONT>                                    if (handshakeAcknowledged) {<a name="line.233"></a>
<FONT color="green">234</FONT>                                            server.handleDatagramPacket(datagramPacket);<a name="line.234"></a>
<FONT color="green">235</FONT>                                    } else {<a name="line.235"></a>
<FONT color="green">236</FONT>                                            verifyAcknowledgment(datagramPacket);<a name="line.236"></a>
<FONT color="green">237</FONT>                                    }<a name="line.237"></a>
<FONT color="green">238</FONT>                            }<a name="line.238"></a>
<FONT color="green">239</FONT>                    }<a name="line.239"></a>
<FONT color="green">240</FONT>            }<a name="line.240"></a>
<FONT color="green">241</FONT>    <a name="line.241"></a>
<FONT color="green">242</FONT>            /**<a name="line.242"></a>
<FONT color="green">243</FONT>             * Verifies that the server verifies the handshake request with an '{@value #ACK}' reply to an '{@value ClientEndpointUDP#CONNECT}'. If<a name="line.243"></a>
<FONT color="green">244</FONT>             * it isn't, the message will be buffered in {@link #bufferQueue} until it is.<a name="line.244"></a>
<FONT color="green">245</FONT>             * <a name="line.245"></a>
<FONT color="green">246</FONT>             * @param datagramPacket The response message from the server that must contain the acknowledgment value.<a name="line.246"></a>
<FONT color="green">247</FONT>             */<a name="line.247"></a>
<FONT color="green">248</FONT>            private boolean verifyAcknowledgment(final DatagramPacket datagramPacket) {<a name="line.248"></a>
<FONT color="green">249</FONT>                    final String message = new String(datagramPacket.getData()).trim();<a name="line.249"></a>
<FONT color="green">250</FONT>                    if (!message.equals(ACK)) {<a name="line.250"></a>
<FONT color="green">251</FONT>                            final String msg = "expected acknowledgment '%s' back, but received: '%s'. This message will be buffered.";<a name="line.251"></a>
<FONT color="green">252</FONT>                            LOGGER.debug(String.format(msg, ACK, message));<a name="line.252"></a>
<FONT color="green">253</FONT>                            return handshakeAcknowledged = false;<a name="line.253"></a>
<FONT color="green">254</FONT>                    } else {<a name="line.254"></a>
<FONT color="green">255</FONT>                            LOGGER.debug(String.format("server acknowledged handshake with '%s'", message));<a name="line.255"></a>
<FONT color="green">256</FONT>                            LOGGER.info(String.format("handshake confirmed", message));<a name="line.256"></a>
<FONT color="green">257</FONT>                            if (!bufferQueue.isEmpty()) {<a name="line.257"></a>
<FONT color="green">258</FONT>                                    LOGGER.debug("handling messages from the handshake buffer queue...");<a name="line.258"></a>
<FONT color="green">259</FONT>                                    for (DatagramPacket bufferedDatagramPacket : bufferQueue) {<a name="line.259"></a>
<FONT color="green">260</FONT>                                            server.handleDatagramPacket(bufferedDatagramPacket);<a name="line.260"></a>
<FONT color="green">261</FONT>                                    }<a name="line.261"></a>
<FONT color="green">262</FONT>                            }<a name="line.262"></a>
<FONT color="green">263</FONT>                            return handshakeAcknowledged = true;<a name="line.263"></a>
<FONT color="green">264</FONT>                    }<a name="line.264"></a>
<FONT color="green">265</FONT>            }<a name="line.265"></a>
<FONT color="green">266</FONT>    <a name="line.266"></a>
<FONT color="green">267</FONT>            /**<a name="line.267"></a>
<FONT color="green">268</FONT>             * Returns a server endpoint in case a datagram packet is received from a previously unknown server. Otherwise, nothing is returning and<a name="line.268"></a>
<FONT color="green">269</FONT>             * this method remains blocking (like {@link ServerSocket#accept()}) until a server sends a datagram packet.<a name="line.269"></a>
<FONT color="green">270</FONT>             * &lt;p&gt;<a name="line.270"></a>
<FONT color="green">271</FONT>             * TCP messages received are inherently coupled to a (server) &lt;code&gt;Socket&lt;/code&gt;. To mimic this behavior {@link ClientEndpointUDP}<a name="line.271"></a>
<FONT color="green">272</FONT>             * keeps track of the first connected server and will assume all future communication is with the same server binding.<a name="line.272"></a>
<FONT color="green">273</FONT>             */<a name="line.273"></a>
<FONT color="green">274</FONT>            @Override<a name="line.274"></a>
<FONT color="green">275</FONT>            public ServerEndpoint getServerEndpoint() {<a name="line.275"></a>
<FONT color="green">276</FONT>                    while (server == null &amp;&amp; !datagramSocket.isClosed()) {<a name="line.276"></a>
<FONT color="green">277</FONT>                            ServerUtil.defaultSleep();<a name="line.277"></a>
<FONT color="green">278</FONT>                    }<a name="line.278"></a>
<FONT color="green">279</FONT>                    return server;<a name="line.279"></a>
<FONT color="green">280</FONT>            }<a name="line.280"></a>
<FONT color="green">281</FONT>    <a name="line.281"></a>
<FONT color="green">282</FONT>            /**<a name="line.282"></a>
<FONT color="green">283</FONT>             * @return {@link DatagramSocket#isClosed()}<a name="line.283"></a>
<FONT color="green">284</FONT>             */<a name="line.284"></a>
<FONT color="green">285</FONT>            @Override<a name="line.285"></a>
<FONT color="green">286</FONT>            public boolean isClosed() {<a name="line.286"></a>
<FONT color="green">287</FONT>                    return datagramSocket.isClosed();<a name="line.287"></a>
<FONT color="green">288</FONT>            }<a name="line.288"></a>
<FONT color="green">289</FONT>    <a name="line.289"></a>
<FONT color="green">290</FONT>            /**<a name="line.290"></a>
<FONT color="green">291</FONT>             * Calls {@link DatagramSocket#close()}<a name="line.291"></a>
<FONT color="green">292</FONT>             */<a name="line.292"></a>
<FONT color="green">293</FONT>            @Override<a name="line.293"></a>
<FONT color="green">294</FONT>            public void close() {<a name="line.294"></a>
<FONT color="green">295</FONT>                    datagramSocket.close();<a name="line.295"></a>
<FONT color="green">296</FONT>            }<a name="line.296"></a>
<FONT color="green">297</FONT>    }<a name="line.297"></a>




























































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